Anatomy of gingival microscopy and gingival epithelium

Gingival epithelium

1. MICROANATOMY OF GINGIVA Gingiva consists of two parts : Epithelium (stratified squamous epithelium) Connective tissue.

2. GINGIVAL EPITHELIUM can be divided into : Oral / outer Epithelium - faces the oral cavity Sulcular Epithelium – faces the tooth without being in contact with it. Junctional Epithelium - provides the contact between the tooth and gingiva .

3. General Aspects Of Gingival Epithelium Principal cell type of gingival epithelium is: Keratinocyte Non- keratinocytes Langerhan cells Merkel cells Melanocytes Inflammatory cells

4. Distinct layers or strata of epithelium: A. Stratum Basale B. Startum Spinosum C. Stratum Granulosum D. Stratum Corneum

5. FUNCTIONS OF GINGIVAL EPITHELIUM To protect the deep structures. Selective interchange with oral environment

6. Different types of epithelial surface layers Orthokeratinization Complete keratinization process Superficial horny layer similar to that of skin No nuclei in the str. Corneum Well defined str. Granulosum with keratohyaline granules 15%

7. Parakeratinization Pyknotic nuclei in Str. Corneum Keratohyaline granules are disperse not giving rise to str. Granulosum 75%

8. Non keratinization Superficial cells have viable nuclei No str. Corneum and no str. Granulosum 10%

9. Main protein in gingival epithelium KERATIN composed of Different polypeptide subunit characterized by Their molecular wt Iso -electric point

10. Nonkeratin proteins Keratolinin Involucrin Filaggrin

11. Corneocytes Contains bundles of keratin tonofilaments in matrix of filaggrin . Surrounded by envelop under the cell membrane.

12. In electron microscopy- reveals that keratinocytes are interconnected by- Desmosomes 2. Tight junctions ( zonae occludens )

13. Nonkeratinocytes MELANOCYTES- 1. Are dendritic cells 2. Located in basal and spinus layer 3. Synthesize melanin in the organells called Premelanosomes / Melanosomes

14. LANGERHANS CELL 1. Dendritic cells - suprabasal layers. 2. Belong to Mononuclear phagocyte system 3. Act as antigen presenting cells (APC) 4. Contain g-specific granules ( Birbeck’s granules ) which are rod or flask shaped granules. 5. Marked ATPase activity.

15. MERKEL CELL 1. Located in deeper layer of epithelium 2. Tactile perceptors 3. Free nerve endings.

16. BASAL LAMINA Epithelium is joined by underlying connective tissue by a basal lamina. Thickness– 300-400 A* Lying 400 A* below epithelial basal layer.

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18. 1. The epithelium of gingiva is: (a)Simple squamous epithelium (b)Stratified squamous epithelium (c)Stratified columner epithelium (d) Stratifiedcuboidal epithelium

19. 2. Main protein of gingival epithelium is: (a) Keratolinin (b) Keratin (c) Involucrin (d) Filaggrin